-LRB- CNN -RRB- -- Alleged Boston bomber Dzhokhar Tsarnaev was semi-conscious , wrapped in field gauze and `` covered in blood '' when he arrived late Friday at Beth Israel Hospital in Boston , according to a detailed first-hand account from a senior employee at the hospital .

The source said Tsarnaev appeared to have lost a great deal of blood and was making no sound until he reached the Red Zone Trauma Area , where he began to moan in considerable pain .

He did n't seem to utter any words , the source said .

Approximately 8-10 medical staff were working on him and there were at least two thoracic surgeons present as well as other surgeons . His condition was stabilized very quickly , said the source .

The FBI was inside the trauma room during the stabilization and several other law enforcement agencies were outside the room , including the FBI , Boston police and Beth Israel police , according to the source .

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Other patients were also in the trauma area , separated by curtains , but there were no bombing victims there , the source said .

Tsarnaev was taken to X-ray , had a CT scan and was then taken to the operating room . FBI agents stayed nearby during surgery , the source said .

Within a matter of hours he was moved to an ICU unit on the upper floors of the hospital . There were no other patients in that secure unit for the duration of the time that he was there and Tsarnaev recovered very quickly , the source said .

`` He was in much better shape than most people thought , '' the source said , but had serious wounds to his throat and leg .

He has since been transferred with the help of U.S. Marshals to Federal Medical Center , Devens -- a federal prison specializing in long-term medical care , about 40 miles west of Boston .

At Devens , he is locked inside a 10-by-10-foot cell with a steel door , a slot for food and an observation window , a prison spokesman said Sunday .

Tsarnaev is now able to speak and has been interacting with medical staff , spokesman John Colautti said .

After disasters , hospitals pay it forward

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Source : Dzhokhar Tsarnaev arrived at hospital semi-conscious and ` covered in blood '

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He did n't seem to utter any words , the source says

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Source : His condition was stabilized very quickly